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<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="author" content="wangbo">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab);
      background-size: 200% 200%;
      animation: gradient 15s ease infinite;
      height: 100vh;
    }

    @keyframes gradient {
      0% {
        background-position: 0% 0%;
      }

      50% {background-position: 100% 100%;}

      100% {background-position: 0% 0%; }
    }
  </style>
</head>

<body>
  背景渐变
</body>

</html>